This invention relates to variable timing and power storage circuit arrangements for use in projectiles or rockets to pre-set the time interval between launch of the projectile and the execution of a particular function or functions by the projectile and for providing power storage in such projectiles. The present invention is especially, but not exclusively, suitable for use in radar decoy chaff-dispensing projectiles for initiating a chaff-dispensing operation at a pre-set time interval after launch of the projectile when the projectile is located at the requisite chaff-dispensing location. For the purpose of pre-setting the time interval between launch of the projectile and for deriving electrical power to initiate the chaff-dispensing function at the expiration of said interval electric signals may be transmitted to the projectile or rocket through inductive coupling means which serve to electrically couple the projectile to control means when the projectile is located within its launching barrel.